[SEBA-679] Fixing documentation for the tag_and_push.sh script in the VOLTHA chart

Change-Id: I422c60d81832140929ddc8df32807025853a5f64
diff --git a/charts/voltha.md b/charts/voltha.md
index 2a6e04b..cf35276 100644
--- a/charts/voltha.md
+++ b/charts/voltha.md
@@ -64,7 +64,7 @@
 cd incubator/voltha
 REPOSITORY=voltha/ TAG=dev VOLTHA_BUILD=docker make build
 cd ~/cord/automation-tools/developer
-bash tag_and_push.sh -t dev -r 192.168.99.100:30500
+bash tag_and_push.sh -f dev -r 192.168.99.100:30500
 ```
 
 This set of commands builds the VOLTHA containers and pushes them to a local